The presets in AmpliTube are sometimes named in a way that "suggests" certain artists and/or songs, but you are right that it is far from clear.
This may not be a helpful answer
but this is one of the reasons I
don't usually play with the stock presets in AmpliTube -- or I use them just as "inspiration" or "platforms" for creating my own presets.
Really, to approximate a given artist's tone, I find the most useful approach is to search online for information about the real gear they use (or used during the period in which I am interested) and then look for similar models in AmpliTube to help build my own rig.
There is, for example,
enormous amounts of online information (perhaps too much!) regarding AC/DC gear and tone. I'm not sure that AmpliTube has
exact matches for the amps, but (for example) I would think that the
JH Gold or
Vintage Metal Lead would be similar to classic AC/DC amps (and, then, probably a Marshall-type cab with
Brit Green or
Brit Anniversary speakers, or some mix of those). Start with all the controls around 5, and adjust to taste.
The guy in Green Day uses modded (for more gain) Marshall Superleads, I think. So your best bet there is something that approximates that -- maybe the
AFD100 from the Slash package? Or one of the several channels in the
Satch VM? Marshal-type cabs with ... maybe
Brit 75 or
Brit V3 speakers? Again, start with all the controls around 5, and adjust to taste. There is, again, a fair amount of info about his gear online.
Offspring ... for earlier records, I am thinking the Mesa/Boogie
Mark IV lead channel? That's available in Amplitube.
I am not sure about cabs/speakers ... but perhaps just stock Mesa cabs? (I think more recently they have used VHT amps, too, but I am not sure AmpliTube includes any VHT-type amps.) There is likely to be info about the Offspring's gear online, though I've not searched for it!
Anyway, that would be my approach: find out about the real gear your favorite artists use, and try to approximate a similar rig in AmpiTube.